The present invention relates to a device for providing protection against hypoxia and smoke, the device comprising a mouth-and-nose breathing mask fitted with a demand regulator, optionally accompanied with smoke-protection goggles, and designed to be fed from a source of oxygen and to dilute the oxygen with air taken from the environment when the ambient pressure does not require a pure oxygen feed.
To protect crew members of a fixed wing or rotary wing aircraft fitted with such a device or headgear against NBC (nuclear-biological-chemical) attack proposals have already been made to associate the device with a hood surrounding the head and the neck, and apt to be sealingly connected to the mask.
That solution is not entirely satisfactory. In the event of an NBC threat, crew members must wear their hoods from the beginning of a mission that runs the risk of NBC attack, and under the best of circumstances such hoods have small openings and are very uncomfortable, even when there is no need to wear a breathing mask, e.g. at low altitude.
Also known are protection devices for use on the ground or at low altitude, comprising a face cover which surrounds the eyes and is fitted with means for being put in place on the face and for being held on, and also including a mouth-and-nose mask fitted with an admission coupling for breathing gas (generally filtered air provided by a blower) and a breathe-out valve leading to the atmosphere thorough the face cover. On its own, such a device does not provide adequate protection against NBC attack, to which aircraft pilots, and in particular the pilots of helicopters and transport airplanes, may be subject.
An object of the present invention is to provide a device for protection against hypoxia and smoke which can be used either separately where there is no NBC risk, or else in combination with a hood which, when worn on its own (e.g. during periods of flight at low altitude) is much less uncomfortable than conventional hoods.
To this end, there is provided a device having:
a face cover provided with a flexible gasket surrounding the eyes to protect them against smoke, sealing means at its periphery, and a closable coupling to a filtered air feed;
a mouth-and-nose (oronasal) mask placed in the face cover, fixed thereto, and fitted with a demand regulator whose inlet is provided with a coupling to an oxygen feed source and whose exhaust is connected directly to atmosphere through the face mask via an exhaust valve, the breathe-in and breathe-out paths in the regulator being separated by partitions ; and
means for retaining the face cover on the face of a wearer.
Such a device can include a conventional demand regulator suitable for being fed from an oxygen supply ; the core thereof is retained, and is associated with a mask fitted with a face gasket.
The breathe-in portion of the regulator, inside the partition or case which defines the breathe-in path, is generally connected to internal ventilation means of the face cover, enabling the volume around the head to be ventilated.
When such a device is used for missions on which there is no NBC threat, it is possible to provide the face cover with means for donning and holding the mask on the face, which comprise an inflatable harness and a block removably secured to the front face of the face cover. The device can then be put into place in conventional manner. The harness can be designed to be usable by crew members regardless of whether they are wearing helmets, as described in document FR-A-2 710 272 or U.S. Pat. No. 5,488,948.
In a modified embodiment, suitable when the risk of hypoxia and smoke is the only expected risk and providing the pilot is wearing a helmet, a hoop can be fixed to the helmet using the prongs which are conventionally used for securing a mask. Under such circumstances, the hoop should be designed to receive the face cover in sealed manner. The face of the pilot is then exposed to the environment, with the exception of the breathing passages and the zone surrounding the eyes which are protected by flexible gaskets. Under such circumstances, a harness is unnecessary.
In contrast, when there exists an NBC risk, the crew members put on their hoods before the start of the mission. Conventionally, such a hood has a portion enveloping the head and provided with a neck gasket, and a portion that forms a bib which extends over the flying suit. Unlike conventional hoods, a hood designed to be used with a device of the kind described above can include a very large opening leaving uncovered the mouth, the nose, and the eyes. A hood of this kind is not as uncomfortable to wear as are conventional hoods.
An air-tight chamber must be established around the heads of crew members when an NBC threat is present. The device described above makes it possible to adopt various solutions to establish such a sealed enclosure. NBC protection may be provided in particular by generating an over pressure in the pilot""s head volume.
One solution consists in fitting the hood with a hoop of the kind described in U.S. patent application Ser. No. 09/072188, said hoop being secured by prongs which engage in receptacles in the helmet. Under such circumstances, the face cover can be designed to be fixed on the hoop, using means which may be as described in that patent application.
The breathe-in path of the demand regulator is typically connected to ventilation means inside the face cover, which may be constituted by two pipes opening out inside the face cover. The mask can be fed with filtered air when there is no need for oxygen enrichment. A filtered air feed is provided under small over pressure so as to sweep through the hood and/or the helmet, thereby putting the head enclosure under pressure.
The above features and others appear more clearly on reading the following description of particular embodiments, given by way of non-limiting example. The description refers to the accompanying drawings.